High Luminous Flux Warm White Solid State Lighting Device

ABSTRACT

A high luminous flux warm white solid state lighting device with a high color rendering is disclosed. The device comprising two groups of semiconductor light emitting components to emit and excite four narrow-band spectrums of lights at high luminous efficacy, wherein the semiconductor light emitting components are directly mounted on a thermal effective dissipation member; a mixing cavity for blending the multi-spectrum of lights; a back-transferred light recycling member deposited on top of an LED driver and around the semiconductor light emitters; and a diffusive member to diffuse the mixture of output light from the solid state lighting device. The solid state lighting device produces a warm white light with luminous efficacy at least 80 lumens per watt and a color rendering index at least 85 for any lighting application.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional of commonly owned U.S. Utility patentapplication Ser. No. 12/336,107, filed Dec. 16, 2008, entitled: HighLuminous Flux Warm White Solid State Lighting Device, this Utilitypatent application incorporated by reference herein.

FIELD OF INVENTION

The invention relates generally to solid state lighting devices, as wellas related components, systems and methods, and more particularly tomethods to make warm white light with high color rendering and highluminous efficacy.

BACKGROUND OF THE INVENTION

It is well known that incandescent light bulbs are very energyinefficient light sources—about 90% of the electricity they consume isreleased as heat rather than light. Fluorescent light bulbs are by afactor of about 10 more efficient, but are still less efficient than asolid state semiconductor emitter, such as light emitting diodes, by afactor of about 2.

In addition, incandescent light bulbs have a relatively short lifetime,i.e., typically about 750 to 1000 hours. Fluorescent bulbs have a longerlifetime (e.g., 10,000 to 20,000 hours) than incandescent lights, butthey contain mercury, not an environment friendly light source, and theyprovide less favorable color reproduction. In comparison, light emittingdiodes have a much longer lifetime (e.g., 50,000 to 75,000 hours).Furthermore, solid state light emitters are very environmentally “green”light sources and they can achieve very good color reproduction.

Accordingly, for these and other reasons, efforts have been ongoing todevelop solid state lighting devices to replace incandescent lightbulbs, fluorescent lights and other light-generating devices in a widevariety of applications. In addition, where light emitting diodes (orother solid state light emitters) are already being used, efforts areongoing to provide improvement with respect to energy efficiency, colorrendering index (CRI Ra), luminous efficacy (lm/W), color temperature,and/or duration of service, especially for indoor applications.

A semiconductor light emitting device utilizing a blue light emittingdiode having a main emission peak in blue wavelength range from 400 nmto 490 nm, and a luminescent layer containing an inorganic phosphor thatabsorbs blue light emitted by the blue LED and produces an excitinglight having an emission peak in a visible wavelength range from greento yellow (in the range of about 525 nm to 580 nm) with spectrumbandwidth (full width of half maximum, simply refer to FWHM) about 80 to100 nm.

Almost all the known light emitting semiconductor devices utilizing blueLEDs and phosphors in combination to obtain color-mixed light of theemission light from the blue LEDs and excitation light from thephosphors use YAG-based or silicate-based luminescent layer asphosphors. Those solid state lighting devices have typically white colortemperature about 5000 K to 8500 K with low color rending index Ra about60˜70. This white solid state lighting device is not desirable for someapplications, like indoor applications, which require warm white colorabout 2700 K to 3500 K with a high color rending index Ra above 80.

Known warm white semiconductor light emitting solutions and their lowluminous efficacy issues are shown at the followings:

1. Blue LED with mixture YAG-based or silicate-based phosphors (forexciting yellow light) and nitrides or sulfides phosphors (for excitingred light) for a warm white light. YAG-based or silicate-based phosphorsexcite a broad-band yellow light having a full spectrum range from 500nm to 650 nm with FWHM about 80˜100 nm. But this yellow excitation lighthas a shortage in red and bluish green wavelength range, which limitsits color rendering index Ra less than 70. Adding a red phosphor to theyellow phosphor can compensate for a shortage of red light, resulting inimproved color rendering index about 75˜80. But the red phosphor absorbsthe emission blue light (with a peak wavelength around 460 nm) andexcites a red light (with a peak wavelength around 620 nm), which causesa significant Stoke-shift issue in photonic energy loss. Another issuewith the mixture of yellow and red phosphors is the broad-band spectrumdistribution of the excitation light, where luminous flux contributionis low at two edge spectrums range due to the low sensitivity of red andbluish green wavelength light to the human eye.2. Blue LED with mixture YAG-based or silicate phosphors (for excitinggreen light) and nitrides or sulfides phosphors (for exciting orangelight) for a high color rendering warm white light. The mixture of greenand orange phosphors can compensate for the shortage of red light andbluish green light, resulting in warm white with high color renderingindex above 80. But it has three issues which will cause low luminousefficacy: a) multi-phosphors self-absorption loss of the photons excitedfrom the green and orange phosphor particles; b) Stoked-shift loss fromblue-to-red wavelength conversion; c) low luminous flux contributionfrom the red and bluish green wavelength in the broad-band spectrumdistribution edge of the excitation light.3. Blue LED with YAG-based or silicate-based phosphors (for excitingyellow light or blue shifting yellow light) and mixing with asemiconductor emitting red/amber color light for a high color renderingwarm light. Adding red/amber semiconductor emitters directly to thesolid state white lighting device can solve the issues ofmulti-phosphors self-absorption loss and Stokes shift loss of theblue-to-red wavelength conversion. But it still suffers from a lowluminous flux contribution issue from the red and bluish greenwavelength range in the broad-band spectrum distribution of theexcitation light. And it still has a shortage of bluish greenwavelength. Besides this, more efforts are ongoing to improve the lightmixture from the multi-color semiconductor light emitters.

BRIEF SUMMARY OF THE INVENTION

To overcome low luminous efficacy and low color reproduction issues fromthe known warm white semiconductor light emitting device. The presentapplication discloses a system and a method of a solid state lightingdevice to generate a high color rendering warm white light at a highluminous efficacy. The solid state lighting device includes a firstgroup of semiconductor light emitting components generating a mixturelight of an emitted first spectrum blue light and an excited secondspectrum yellow light having a narrow bandwidth; a second group ofsemiconductor light emitting components emitting at least a thirdspectrum narrow-band reddish orange light to compensate for the shortageof red wavelength in the narrow-band yellow excitation light; a fourthspectrum narrow-band green light either excited from the first group ofsemiconductor light emitting components or emitted from the second groupof semiconductor light emitting components to compensate for theshortage of bluish green wavelength in the narrow-band yellow excitationlight; a diffusive output window member having an air space to thesemiconductor light emitting components to diffuse the first and secondgroups of the emission lights; a back-transferred light recycling memberto convert the back-transferred light into a forward-transferred light;and a light mixing cavity between the groups of the semiconductor lightemitting components, the back-transferred light recycling member and thediffusive member for mixing the multi-spectrums lights. The first andsecond groups of semiconductor light emitting components directlymounted on a thermal effective dissipation member. If a current issupplied to the power string line, a mixture of light from the first andsecond groups of the semiconductor light emitting components produce ahigh luminous flux warm white light with luminous efficacy at least 80lumens per watt and color rendering index at least 85 for any indoorlighting applications.

In one embodiment, the first group of the semiconductor light emittingcomponents generates a high luminous efficacy sub-mixture of white lightfrom an emitted blue light and an excited yellow light with a peakwavelength of 550 nm˜575 nm and a spectrum width FWHM less than 75 nm.The chromaticity coordinates of a sub-mixture of white light is closedto the blackbody locus on 1931 CIE. The second group of semiconductorlight emitting components generates a sub-mixture of yellowish orangelight from the semiconductor reddish orange emitters and thesemiconductor green emitters, which all have state-of-art high luminousefficacy. The second group of lights compensates for the shortage of redand bluish green wavelength range in the first group of narrow-bandyellow excitation light. The mixture of the first and secondsemiconductor emitting components produces a high luminous flux warmwhite light with a high luminous efficacy, as well as a high colorrendering index.

In another embodiment, the first group of the semiconductor lightemitting components comprises a semiconductor blue light emitter; ayellow phosphor layer to absorb blue light and excite a yellow lightwith a spectrum width FWHM less than 75 nm; and a green phosphor layerwith a space to a yellow phosphor layer to absorb the leakage blue lightand convert it into a green light with a spectrum width FWHM less than75 nm. The sub-mixture of the emitted blue light and excited yellow andgreen lights has chromaticity coordinates above a blackbody locus on1931 CIE at improved luminous efficacy. The second group of thesemiconductor light emitting components has a semiconductor reddishorange emitters with a state-of-art high luminous efficacy to compensatefor the shortage of red wavelength in the first group sub-mixture oflight. The mixture of the first and second semiconductor emittingcomponents produce a high luminous flux warm white light with highluminous efficacy, as well as a high color rendering index.

In another embodiment, the first group of the semiconductor lightemitting components includes at least one semiconductor light emitterarray in a single package having a high reflection coating on the topsurface of a substrate. A first phosphor layer deposited on top of thereflective substrate to cover both the semiconductor light arrayemitters and the space between the semiconductor light array emitters toexcite a second spectrum of yellow light with a narrow bandwidth. Asecond phosphor layer on top of the first phosphor layer to excite athird spectrum of green light from the leakage of first spectrum lightto improve its luminous efficacy.

In another embodiment, a method of mixing the lights from the two groupsof the semiconductor light emitting components is provided. The methodincludes a light mixing cavity between the semiconductor light emittingcomponents, the back-transferred light recycling member and the lightdiffusive member. The back-transferred light recycling member willconvert the backscattering light from the diffusive member and theemission/excitation light from the semiconductor light emittingcomponents into a forward-transferred light and export from thediffusive output window. The lights from the two groups of thesemiconductor light emitting components get completely mixed beforeexporting through the diffusive output window of the solid statelighting device.

In another embodiment, the back-transferred recycling member includes awavelength conversion layer. The wavelength conversion layer willconvert the emission of short wavelength light into a desired visiblewavelength to recycle the back-transferred light and at same time toadjust the mixing light chromaticity.

The foregoing has outlined rather broadly the more pertinent andimportant features of the present invention in order that the detaileddescription of the invention that follows may be better understood sothat the present contribution to the art can be more fully appreciated.Additional features of the invention will be described hereinafter whichform the subject of the claims of the invention. It should beappreciated by those skilled in the art that the conception and thespecific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of one embodiment of a solid statelighting device according to the present invention;

FIG. 2 is a CIE 1931 diagram;

FIG. 3 is a cross sectional view of one embodiment of a solid statelighting device according to the present invention;

FIG. 4 is a cross sectional view of one embodiment of a solid statelighting device according to the present invention; and

FIG. 5 is a cross sectional view of one embodiment of a solid statelighting device according to the present invention.

Similar reference characters refer to similar parts throughout theseveral views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

An object of the present invention is to suppress certain wavelengthspectrums shortage, Stoke-shift loss of blue-to-red wavelengthconversion, multi-phosphors absorption loss and radiance power loss atred/bluish green tail range of a broad-band excited yellow light in awarm white solid state lighting device by utilizing a narrow-bandexcited yellow light mixing with semiconductor emitting yellowish orangelight, in combination with a forth spectrum green light in a mixingcavity so as to provide a solid state lighting device or solid statelighting system in warm white color temperature range exhibiting aluminous flux higher than known white-light emitting semiconductordevices and a high color rendering index above 85.

The First Aspect of the Present Invention

According to the first aspect of the present invention as shown in FIG.1, a solid state lighting device 10 comprising a first group ofsemiconductor light emitting components 20; a second group ofsemiconductor light emitting components 30; a single power string line90; a back-transferred recycling member 60; a diffusive member 40 and amixing cavity 45 formed inside of the above members.

The first group of semiconductor light emitting components 20 generate ahigh luminous efficacy sub-mixture of white light. The first group ofsemiconductor light emitting components 20 includes at least onesemiconductor light emitter 80 for a first spectrum short wavelengthlight 120 and at least one down-conversion phosphor layer 100 on top ofthe semiconductor light emitter 80 for exciting a second spectrum ofyellow light 130 with a narrow bandwidth. Wherein, the spectral emissionof the first spectrum light 120 has a peak wavelength range from 440nm˜465 nm; the spectral emission of the second spectrum light 130 has apeak wavelength range from 550 nm˜575 nm at a spectrum width FWHM lessthan 75 nm. In this excited narrow-band yellow light spectrumdistribution, the bluish green tail wavelength range from 500 nm˜520 nmand red tail wavelength range from 620 nm˜650 nm have been significantlycut-off to reduce photons energy loss at these human eye lesssensitivity spectrums range.

The second group of semiconductor light emitting components 30 generateat least a third spectrum of reddish orange light 140. The spectralemission of the third spectrum light 140 has a peak wavelength rangefrom 610 nm˜620 nm with FWHM less than 25 nm. The second group ofemitted reddish orange light 140 will compensate for the shortage ofbluish green light in the first group of yellow excite light 130.

A fourth spectrum of green light 150 either exciting from the firstgroup of semiconductor light emitting components 20 or emitting from thesecond group of semiconductor light emitting components 30. The spectralemission of the fourth spectrum of light 150 has a peak wavelength rangefrom 525 nm˜535 nm. The fourth spectrum of green light 150 willcompensate for the shortage of bluish green light in the first group ofyellow excited light 130.

A dome lens 75 from a high refractive index above 1.5 may be depositedon top of each semiconductor light emitter to reduce total internalreflection loss.

The single power string line 90 electrically connects each of the firstgroup of semiconductor light emitting components 20 and each of thesecond group of semiconductor light emitting components 30.

A light mixing cavity 45 is formed inside of the semiconductor lightemitting components (LEDs), the LED driver board 55 and the diffusiveoutput window 40. The diffusive output window 40 having an air space tothe semiconductor light emitting components 20, 30. A back-transferredrecycling member 60 is deposited inside the light mixing cavity 45 ontop of the LED driver board 55 and around the semiconductor lightemitting components 20, 30 to convert back-transferred light into aforward-transferred light and exported from the diffusive output window40.

If a current is supplied to the power string line 90, a combination ofthe first spectrum light 120 and the second spectrum light 130 emittingfrom the first group of semiconductor light emitting components 20, inan absence of any additional light, produce a sub-mixture of white lightwith corrected color temperature (CCT) in a 4500 K˜6000 K range and aluminous efficacy greater than 90 lm/W; a combination of the thirdspectrum light 140 and the fourth spectrum light 150, in an absence ofany additional light, produce a sub-mixture of yellowish orange lightwith a luminous efficacy greater than 90 lm/W; and a combination of 1)Light producing from the first group of semiconductor light emittingcomponents 20, and 2) Light producing from the second group ofsemiconductor light emitting components 30 produces a mixture of warmwhite light within ten MacAdam ellipses with at least one point on ablackbody locus, as shown in FIG. 2, having a correct color temperaturein a 2700 K˜3500 K range with a color rendering index (CRI) at least 85.

In some embodiments according to the first aspect of the presentinvention, the solid state lighting device 10 may comprise the firstspectrum light 120 and the second spectrum light 130 from the firstgroup of semiconductor light emitting components 20, producing a mixtureof light having (x,y) coordinates on 1931 CIE within an area enclosed byfour line segments having (x,y) coordinates (0.325,0.310),(0.360,0.330), (0.370,0.400), and (0.320,0.390); and the third spectrumlight 140 and the fourth spectrum light 150 from the second group ofsemiconductor light emitting components 30, producing a mixture of lighthaving (x,y) coordinates on 1931 CIE within an area enclosed by fourline segments having (x,y) coordinates (0.500,0.450), (0.525,0.465),(0.565,0.425), and (0.520,0.420);

In some embodiments according to the first aspect of the presentinvention, the solid state lighting device 10 may comprise semiconductorlight emitting components 20 (LEDs) directly packaged on a thermaleffective dissipation member 160.

As shown in FIG. 5, in some embodiments according to the first aspect ofthe present invention, the solid state lighting device 10 may comprisesemiconductor light emitting components 20 (LEDs) directly packaged onthe side wall 67 of the solid state lighting device body 65 for thermaleffective dissipation and have a reflective member 70 to redirect lightinto a forward-transferred light and mixed at the mixing cavity 45before exported from the diffusive output window 40.

In some embodiments according to the first aspect of the presentinvention, the solid state lighting device 10 may comprise aback-transferred light recycling component 60 including a wavelengthconversion component 50. The wavelength conversion component 50 isdeposited on top of the back-transferred recycling member 60. Thewavelength conversion component 50 absorbs backscattering shortwavelength light from the diffusive member 40 and emission light fromthe semiconductor emitting components 20, and converts it into desiredvisible light to adjust the mixing light chromaticity.

In some embodiments according to the first aspect of the presentinvention, the phosphor layer in the first group of semiconductor lightemitting components 20 may be quantum dots, exciting a yellow light witha narrow bandwidth of FWHM less than 75 nm.

In some embodiments according to the first aspect of the presentinvention, the first group of semiconductor light emitting components 20may include at least one semiconductor emitter 80 for emitting a firstspectrum of blue or near UV light; at least a first phosphor layer 100on top of the semiconductor emitter 80 excited by the first spectrumlight 120 and produce a second spectrum of yellow light 130; at least asecond phosphor layer 110 on top of the first phosphor layer 100 excitedby the leakage from the first spectrum of light 120 and produces a forthspectrum of green light 150. It may have a transparent dome lens 75deposited between the first phosphor layer 100 and the second phosphorlayer 110.

In some embodiments according to the first aspect of the presentinvention, the first group of semiconductor light emitting components 20may include a semiconductor emitter 80 for emitting near-UV excitinglight in a center wavelength range 380 nm˜420 nm and at least twoquantum dots to absorb the near-UV exciting light and produce a firstspectrum of blue light 120 and a second spectrum of yellow light 130.

In some embodiments according to the first aspect of the presentinvention, the second group of semiconductor light emitting components30 may include a green semiconductor light emitter and a reddish orangesemiconductor emitter. The green semiconductor light emitter and thereddish orange semiconductor light emitter are packaged on a singlesubstrate chip 70. A high refractive index dome lens is used toencapsulate the co-package dies. The green and reddish orange light aremixed in the encapsulation resin to produce a mixture of yellowishorange light.

In some embodiments according to the first aspect of the presentinvention, the second group of solid state light components 30 mayinclude a green semiconductor emitter and a phosphor excited by thegreen light to emit a reddish orange light. A combination of the emittedgreen light and the excited reddish orange light produce a mixture oflight having (x,y) coordinates on 1931 CIE within an area enclosed byfour line segments having (x,y) coordinates (0.500,0.450),(0.525,0.465), (0.565,0.425), and (0.520,0.420).

The Second Aspect of the Present Invention

According to the second aspect of the present invention as shown in FIG.3, a solid state lighting device comprising a first group ofsemiconductor light emitting components 20 in a single package; a secondgroup of semiconductor light emitting components 30; a single powerstring line 90; a back-transferred recycling member 60; a diffusivemember 40 and a mixing cavity 45 formed inside of the above members.

The first group of semiconductor light emitting components 20 include asemiconductor light emitter array 80 packaged on a single substrate 70having a high reflection coating on the top surface to produce a firstspectrum of short wavelength light 120; a first phosphor layer 100deposited on top of the reflective substrate 70 to cover the entiresubstrate along with the first group of semiconductor light emittingcomponents 20 and the second group of semiconductor light emittingcomponents 30 to excite a second spectrum of yellow light 130 with anarrow bandwidth; and at least a second phosphor layer 110 on top of thefirst phosphor layer 100 to excite a third spectrum of green light 140from the leakage of the first spectrum light 120 to improve its luminousefficacy.

In a addition, a short-pass dichroic filter can be placed on top of saidfirst group of semiconductor light emitting components.

The second group of semiconductor light emitting components 30 generatesat least a fourth spectrum of reddish orange light 150 to compensate forthe shortage of red wavelength in first group of excited yellow light.

The single power string line 90 electrically connects to each of thefirst group of semiconductor light emitting components 20 and each ofthe second group of semiconductor light emitting components 30.

A light mixing cavity 45 is formed inside of the semiconductor lightemitting components 20, 30 (LEDs), the LED driver board 55 and thediffusive output window 40. The diffusive output window 40 having an airspace to the semiconductor light emitting components 20, 30. Aback-transferred recycling member 60 is deposited inside the lightmixing cavity 45 on top of the LED driver board 55 and around thesemiconductor light emitting components 20, 30 to convertback-transferred light into a forward-transferred light and exports thelight from the diffusive output window 40.

Wherein, the spectral emission of the first spectrum of light 120 fromthe first group of semiconductor light emitting components 20 has acenter wavelength range from 440 nm˜465 nm; the spectral emission of thesecond spectrum of light 130 from the first group of semiconductor lightemitting components 20 has a center wavelength range from 550˜575 nmwith FWHM less than 75 nm; the spectral emission of the third spectrumof light 140 from the first group of semiconductor light emittingcomponents 20 has a center wavelength range from 525 nm˜540 nm with FWHMless than 75 nm; and the spectral emission of the fourth spectrum oflight 150 from said second group of semiconductor light emittingcomponents 30 has a center wavelength range from 610 nm˜620 nm with FWHMless than 25 nm. In the narrow-band of exciting yellow light, the bluishgreen tail wavelength range from 500 nm˜520 nm and red tail wavelengthrange from 620 nm˜650 nm have been significantly cut-off to reducephotons energy loss of the excited yellow light at these human eye lesssensitivity spectrums range. The narrow-band of yellow excitation lightand additional green phosphor on top of the yellow phosphor will enhancethe luminous efficacy of the sub-mixture of greenish white light.

If a current is supplied to the power string line 90, the first spectrumemission of light 120, second spectrum of excitation light 130 and thirdspectrum of excitation light 140 from the first group of semiconductorlight emitting components 20, produces a mixture of light having (x,y)coordinates on 1931 CIE within an area enclosed by four line segmentshaving (x,y) coordinates (0.325,0.310), (0.360,0.330), (0.370,0.400),and (0.320,0.390) with an enhanced luminous efficacy at least 90 lm/W;and a combination of 1) Light produced from the first group of solidstate lighting components 20, and 2) Light produced from the secondgroup of solid state lighting components 30 produces a mixture of lightwithin ten MacAdam ellipses with at least one point on a blackbodylocus, having a correct color temperature in a 2700 K˜3500 K range witha color rendering index (CRI) at least 85.

In some embodiments according to the second aspect of the presentinvention, the first group of semiconductor light emitting components 20include a semiconductor light emitter array 80 for emitting blue lightin a center wavelength range of 450 nm˜465 nm.

In some embodiments according to the second aspect of the presentinvention, the first group of semiconductor light emitting components 20include a semiconductor light emitter array 80 for emitting near UVlight in a center wavelength range of 380 nm˜420 nm.

In some embodiments according to the second aspect of the presentinvention, the first group of the semiconductor light emittingcomponents 20 include a dome 75 from a high refractive index resindeposited on top of the second phosphor layer 110 to reduce totalinternal reflection loss.

The Third Aspect of the Present Invention

According to the third aspect of the present invention as shown in FIG.4, a solid state lighting device 10 comprising a group of semiconductorlight emitting components 20 including a semiconductor light emitterarray 80 having more than one emission light spectrum; one single powerstring line 90; one back-transferred recycling member 60; one diffusivemember 40 and a mixing cavity 45 formed inside of the above members.

The semiconductor light emitter array 80 includes a semiconductor bluelight emitter and a semiconductor reddish orange light emitter; a firstphosphor layer 100 covering all of the semiconductor light arrayemitters 80 and the space between the semiconductor light array emittersto excite a third spectrum of yellow light; and at least a secondphosphor layer 110 on top of the first phosphor layer 100 to excite afourth spectrum of green light from the leakage blue light.

If a current is supplied to the power string line 90, a combination of afirst spectrum of emitted blue light 120, a second spectrum of emittedreddish orange light 130, a third spectrum of excited yellow light 140from the leakage blue light, and a forth spectrum of excited green light150 from the leakage blue light produces a mixture of light within tenMacAdam ellipses with at least one point on a blackbody locus, having acorrect color temperature in a 2700 K 3500 K range with a colorrendering index (CRI) at least 85, as well as a high luminous efficacyat least 90 lm/W.

In some embodiments according to the third aspect of the presentinvention, the first group of the semiconductor light emittingcomponents 20 includes a dome lens 75 from a high refractive index resindeposited on top of the second phosphor layer 110 to reduce totalinternal reflection loss.

It is understood that the above description is intended to beillustrative and not restrictive. Although various characteristics andadvantages of certain embodiments of the present invention have beenhighlighted herein, many other embodiments will be apparent to thoseskilled in the art without deviating from the scope and spirit of theinvention disclosed. The scope of the invention should therefore bedetermined with reference to the claims contained herewith as well asthe full scope of equivalents to which said claims are entitled.

Now that the invention has been described,

1. A solid state lighting device comprising: a first group ofsemiconductor light emitting components emitting a first spectrum ofprimary light; a first wavelength down-conversion layer on top of saidfirst group of semiconductor light emitting components exciting a secondspectrum of yellow light having a narrow bandwidth; a second wavelengthdown-conversion layer on top of said first wavelength down-conversionlayer exciting a third spectrum of light having a peak wavelengthbetween said first spectrum of primary light and said second spectrum ofyellow light; a second group of semiconductor light emitting componentsemitting a fourth spectrum of light having a peak wavelength longer thansaid first spectrum of primary light and said second spectrum of yellowlight; a color mixing cavity having a diffusive output window mixingsaid first spectrum of primary light, said second spectrum of yellowlight, said third spectrum of light and said fourth spectrum of light; alight recycling reflector member around an interior wall of said solidstate lighting device, said light recycling reflector member surroundingsaid first group of semiconductor light emitting components and saidsecond group of semiconductor light emitting components; and a powerline electrically connected to said first group of semiconductor lightemitting components and said second group of semiconductor lightemitting components.
 2. The solid state lighting device according toclaim 1, further comprising: said first spectrum of primary light havinga peak wavelength range from about 440 nm to 465 nm; said secondspectrum of yellow light having a peak wavelength range from about 550nm to 575 nm and a narrow bandwidth with full width at half maximum lessthan 75 nm; said third spectrum of light having a peak wavelength rangefrom about 525 nm to 540 nm and a narrow bandwidth with full width athalf maximum less than 75 nm; and said fourth spectrum of light having apeak wavelength range from about 610 nm to 620 nm and a narrow bandwidthwith full width at half maximum less than 25 nm.
 3. The solid statelighting device according to claim 1, further comprising: said firstgroup of semiconductor light emitting components emitting a near-UVprimary light having a peak wavelength range from about 380 nm to 420nm; and said first wavelength down-conversion layer comprising a mixtureof blue quantum dots, green quantum dots and yellow quantum dots, saidfirst wavelength down-conversion layer exciting a blue spectrum of lighthaving a peak wavelength from about 440 nm to 465 nm, a green spectrumof light having a peak wavelength from about 525 nm to 540 nm and ayellow spectrum of light having a peak wavelength from about 550 nm to575 nm and a narrow bandwidth with full width at half maximum less than75 nm.
 4. The solid state lighting device according to claim 1, whereinsaid first group of semiconductor light emitting components furthercomprising: a semiconductor light emitter emitting a spectrum of primaryblue light; a yellow wavelength conversion layer on top of saidsemiconductor light emitter exciting a spectrum of yellow light having apeak wavelength from about 550 nm to 575 nm and a narrow bandwidth withfull width at half maximum less than 75 nm; and a green wavelengthconversion layer on top of said yellow wavelength conversion layerexciting a spectrum of green light having a peak wavelength from about525 nm to 540 nm.
 5. The solid state lighting device according to claim1, wherein said second group of semiconductor light emitting componentsfurther comprising a green semiconductor light emitter and a reddishorange semiconductor light emitter emitting a spectrum of yellow orangelight, said green semiconductor light emitter and said reddish orangesemiconductor light emitter being packaged on a single substrate chip.6. The solid state lighting device according to claim 1, furthercomprising: a body, said body having a side wall; said first group ofsemiconductor light emitting components being packaged on said side wallof said body; said second group of semiconductor light emittingcomponents being packaged on said side wall of said body; and areflective member positioned under said side wall of said body.
 7. Thesolid state lighting device according to claim 1, wherein said diffusiveoutput window further comprising a dome shape.
 8. The solid statelighting device according to claim 1, further comprising a wavelengthconversion layer on top of said light recycling reflector member.
 9. Asolid state lighting device comprising: a substrate; a first group ofsemiconductor light emitting components being packaged on a single lightemitting device on said substrate, said first group of semiconductorlight emitting components emitting a first spectrum of primary light; afirst wavelength down-conversion layer covering said first group ofsemiconductor light emitting components and covering said substrate,said first wavelength down-conversion layer exciting a second spectrumof yellow light having a narrow bandwidth with full width at halfmaximum less than 75 nm; a second wavelength down-conversion layer ontop of said first wavelength down-conversion layer exciting a thirdspectrum of light having a peak wavelength between said first spectrumof primary light and said second spectrum of yellow light; a secondgroup of semiconductor light emitting components emitting a fourthspectrum of light having a peak wavelength longer than said firstspectrum of primary light, said second spectrum of yellow light and saidthird spectrum of light; a color mixing cavity having a diffusive outputwindow mixing said first spectrum of primary light, said second spectrumof yellow light, said third spectrum of light and said fourth spectrumof light; a light recycling reflector member; and a power lineelectrically connected to said first group of semiconductor lightemitting components and said second group of semiconductor lightemitting components.
 10. The solid state lighting device according toclaim 9, further comprising: said first spectrum of primary light havinga peak wavelength range from about 440 nm to 465 nm; said firstwavelength conversion layer and said second wavelength conversion layerhaving YAG or Silicate based phosphor micro-particles; and said thirdspectrum of light having a peak wavelength range from about 525 nm to540 nm and a narrow bandwidth with full width at half maximum less than75 nm; and said fourth spectrum of light having a peak wavelength rangefrom about 610 nm to 620 nm and a narrow bandwidth with full width athalf maximum less than 25 nm.
 11. The solid state lighting deviceaccording to claim 9, wherein said first wavelength conversion layer andsaid second wavelength conversion layer further comprising a strontiumcalcium thiogallate phosphor doped with divalent europium.
 12. The solidstate lighting device according to claim 9, wherein said firstwavelength conversion layer and said second wavelength conversion layerfurther comprising a nanocrystal coating.
 13. The solid state lightingdevice according to claim 9, further comprising a reflective coating ontop of said substrate.
 14. The solid state lighting device according toclaim 9, further comprising a short-pass dichroic filter on top of saidfirst group of semiconductor light emitting components.
 15. The solidstate lighting device according to claim 9, further comprising atransparent encapsulation resin between said first wavelengthdown-conversion layer and said second wavelength down-conversion layer.16. The solid state lighting device according to claim 9, furthercomprising a dome lens on top of said second wavelength down-conversionlayer.
 17. A solid state lighting device comprising: a substrate; agroup of semiconductor light emitting components being packaged on asingle light emitting device on said substrate, said group ofsemiconductor light emitting components emitting a short wavelengthfirst spectrum of primary light and a long wavelength second spectrum oflight; a first wavelength down-conversion layer covering said group ofsemiconductor light emitting components and covering said substrate,said first wavelength down-conversion layer exciting a third spectrum ofyellow light having a narrow bandwidth; a second wavelengthdown-conversion layer on top of said first wavelength down-conversionlayer exciting a fourth spectrum of light; a color mixing cavity havinga diffusive output window mixing said short wavelength first spectrum ofprimary light, said long wavelength second spectrum of light, said thirdspectrum of yellow light and said fourth spectrum of light; a lightrecycling reflector member; and a power line electrically connected tosaid group of semiconductor light emitting components.
 18. The solidstate lighting device according to claim 17, further comprising: saidshort wavelength first spectrum of primary light having a peakwavelength range from about 440 nm to 465 nm; said long wavelengthsecond spectrum of light having a peak wavelength range from about 610nm to 620 nm; said third spectrum of light having a peak wavelengthrange from about 550 nm to 575 nm and a narrow bandwidth with full widthat half maximum less than 75 nm; and said fourth spectrum of lighthaving a peak wavelength range from about 525 nm to 540 nm and a narrowbandwidth with full width at half maximum less than 75 nm.
 19. The solidstate lighting device according to claim 17, further comprising areflective coating on top of said substrate.
 20. The solid statelighting device according to claim 17, further comprising a dome lens ontop of said second wavelength conversion layer.